Strainer assembly for refrigeration systems



y 1940- v R. A. SANDBERGV 2,202,403

STR AINER ASSEMBLY FOR REFRIGERATION SYSTEMS I Filed my 13, 1957 EFT Eur *rhsmaam yzs;

' su e l ih l s-flm i l r r ut ne; Patro s ght e 'iwra'tion This invention relates toa strainer for reirigerant materialadapted to" be-mounted in a reirig'erator system: The invention-includes a screen protected from brazing material used in method-oi making the strainer-. More specifically, this-invention relates to a brazed together strainer assembly having a wire uniting the parts of the assembly. l Most refrigeration systems require a refriger antstrainer interposed somewhere'in the pathor fl'ow 'of refrigerant-to remove dirt, or-other impurities irom' the refrigerant. These strainer as- 'seinblies must be leak-proof. Since the stra According to this invention, thestrainer hous- .ing'is made'from two'complem'entary drawnor stamped metal cup shaped members united 'to-.

gether by brazing material. The screen is protected from the brazing material'by a sleeve disposed. in the cup members "within the brazin area. The screen itself maybe securely clamped in thesleeve member and thus rigidly held in the housing.

.It is then anobiect 01 this invention to provide a" together strainer assembly with means protecting the straineragain'st clogging by brazing material.

Aiurther objector this having the strainer screen seatedin a separate sleeve member which protects the screen against 1 clpzsing by brazing material.

- Another object of this invention isto form a strainer. housing from two metal cup-shaped members adapted to be brazed together and to protect the strainer screen from being clogged by the brazing material.

Another object of this invention is to-provide an improved method of securing strainer screens in metal housings formed from two complemen-= tary members. 7 1

Another object or this invention'is to provide a process of protecting screen material from brazing flux.

A further object of this invention is to protect a metal screen disposed within a brazing area from clogging by brazing material.

Other and further objects of this invention will become apparent to those skilled in the art from the following detailed description of the 1 i n flcamy is, 19 37, shameless." i I l scam; (c1.'z1 o 1 :nates generally 3 the housing for this invention. The housing Ill has outturned 20 I t invention is to provide a brazed or solderedtogether strainer assembly .crimped'flange l'l defines the in Figure 1 and provides. with theflanges'gii' and annexed sheet ordrawingswhich discloses aprei'erred embodiment of the inventiom 'On thedrawing;

Figure, 1 is aside element view or a strainer assembly according to this-invention;

. Figure. 2is an "enlarged cross-sectional view takelli substantially along the line II- 11 of Figure.

mounted in the sleeve shown'in Figure 2.

figure a is a greatly enlarged fragmentary cross-sectional 'view'of the brazed joint'securing the housing members together in leak-proofreb- I ation and illustrating-the manner in which the As shown on the drawingt m' In Figure 1 the reference'numeral ll d'esig-' the strainer" of annular flanges H and I! at the'ends thereof defining openings giving entrance to the housing. A rim I3 is formedinterinediate the endsoi the housing. I As is shownin Flgure'2, the housing l'o com- 26 prises cup-shaped members and 15 mounted in opposed relation. The members II and ii are stamped or drawn from sheet metal.

The cup member I has an outturned annular flange I; at the'open top thereof.

.Th'ecup member Whas an ou'tturned annular flange l'l provided with aiperipheral rim" ll adapted to be'crimped or spunover the flange-l8 oi the cup member I 4 as shown at I! to provide a seam for holding the cup i'ne'mb'ers II and II 35 in opposed relationto define the housing Ill. The I31 described l1, an annulangroovefl inthe housing. I

. A cylindrical sleeve member 21751; mountedin the housing l0; The sleeve-member' ha the wall thereof bowed outwardly as at 22 intermediate. the ends of the sleeve. The outwardly bowed walls define therebetween a groove 23 for receivingthe peripheral edges ll of a screen 25. The 45 a screen as shown in Figure 2 extends acrossfthe sleeve and may be semi-spherical in shape as shown. The peripheral edges 24 of the screen are securely clamped in the groove 23 by the outwardly bowed walls 22 of the sleeve.

Lips II and 21 extend inwardly from both ends 1 of the sleeve 1| in spaced relation from the cup members H and I5 respectively.

'As-shownin Figure 2, the sleeve 2| snugly fits v in the cup members I4 and I5 and has the inu Figure 3 is a planview or thestrainer'screeh m 7' tend beyond the groove 20 into spaced relation therefrom.

While the cup members it and I are held together by the crimped or spun member IS, the interior of the housing must be absolutely leakproof to prevent the .loss of refrigerant. The seam alone is not sufiicient to render the housing leak-proof. It is thus necessary to integrally secure. the cup membersv i4 and i5 together. in

leak-prooi relation.

According to this invention a wire 28, as shown in Figure 2, composed of 'brazing'material such as copper, bronze, or the like suitable brazing V."

alloys, is disposed around the cup member l4 adjacent the portion I! of the seam,as shown in' Figure 2. The entire assemblyis then-placed in a brazing furnace and heated to brazing temperatures under non-oxidizing or reducing conditions such as, for example, in ahydrogen atmosphere. I

As best shown in Figure 4; the brazing wire 28 melts in the brazing furnace and flows by capillary action between all contiguous surfaces of metal forming the assembly. The films formed by the brazing material are designated by the reference numerals 29 in Figure 4. These films 29 alloy with the metal surfaces and integrally unite the same together. A I

Due to the tenacious capillary attraction of the brazing metal for the metal forming the assem: bly these films 29 flow between all contiguous surfaces of the metal and would rapidly clog the screen 25 unless special precautions are taken to prevent such clogging action. According to this invention, the sleeve 2| serves this purpose of .preventing a clogging of the screen. ,As shown in Figure 4, the films 29 may even flow between the sleeve 2| and the cup members l4 and I5 but the inwardly turned lips 26 and 21 of the sleeve provide wide spaces between the cups i4 and I5 and the sleeve thus breaking the capillary fiow of .the films 29 and preventing these films from reaching the screen. v

- As best shown 'in Figure 4, thesleeve 2| is spaced from-the tops of the cups at the points where the flanges i6 and i1 extend from the cups because the curvatures on the sleeve do not match with the curvature on the cups. This construction provides gaps 30 and 3| which serve as an added protection against flow o! brazing material to the screen. The gaps break the contiguous surfaces between which the films 29 flow. According to this invention, therefore, a brazing operation can be used to unite together housing members in leakproof relation for defining; a housing for a metal screen which under nor mal brazing operations will attract the brazing material and become clogged therewith. According to this invention, the flow of brazing material into contact with the metal screen is prevented and screens of any metal can be used in the assembly.

and numerous details of construction may be varied through a. wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereonotherwise *than necessitated by thepriorart;

Ii claim as my invention: a

l. A strainer assembly comprising complementary metal cups having outturned flanges at their open ends and apertures through their a closed ends. the flange of one cup being crimped around the flange ofthe other cup to secure the cups [together for'defining a housing, a sleeve disposed infsaid housing having the wall thereof bowed'outwardly intermediate the ends of the sleeve to definea rim, said rim being disposed between the flanges of the cups, a wire screen extending across said sleeve and having the peripheral edges thereof secured between the outwardly bowed walls of the sleeve and'a film of brazing material between the flanges of the cup members for rendering the housing air-tight,

said

. Y I am aware that many changes may be made a the top thereof and an aperture throughthe bot- .tom thereof, -a second cup member having an outturned annular flange at the top thereof provided with a rim bent over the flange of the first cup member to hold the cup members together in opposed relation for forming a housing, said flanges being in spacedopposed relation and defining therebetween an annular groove, a sleeve member in said housing having an intermediate portion thereof bowed outwardly to define an annular rim seated in saidgroove, and a strainer extending across said sleeve having the peripheral edges thereof clamped between the outwardly bowed sleeve wall, said sleeve extending beyond'both of theflanges of the cup members and having inturned lips on its ends spaced from the housing wall.

3. A strainer assembly comprising two hollow screen housing parts having juxtaposed portions formed to be connected by a soldered Joint, a screen inside said parts having a'peripheral portion extending into said joint and an intermediate member between said peripheral screen portion and said juxtaposed portions cooperating with said juxtaposed portions to define a capillary path forsolder to flow through, said intermediate member having an inner edge portion removed from the capillar path and which is spaced from the cooperating wall of the adjoining housing part so that solder will. not flow by caplllar action beyond said inner edge portion.

RAY A, SANDBERG.

'25 said sleeve being formed to provide a space be- 

